Oat Fertilizer Recommendations

Nitrogen

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How N guidelines are calculated

We base nitrogen (N) fertilizer guidelines can on the results of the soil (NO₃^--N) test or the consideration of the combination of expected yield, previous crop, and soil organic matter content. The soil nitrate test is appropriate for western Minnesota (see Figure 1).

nitrate recommended counties — Figure 1: The fall soil nitrate test should be used for nitrogen recommendations in the counties that are shaded.

This is the equation for fertilizer N guidelines with the soil nitrate test.

N_rec = (1.3) (EY) - STN_{(0-24 in.)} - N_Pc

Where:

EY = expected yield (lb./acre)

STN = nitrate-nitrogen (NO₃^--N) measured to a depth of 24 in. (lb./acre)

N_pc = amount of N supplied by the previous legume crop (lb./acre).

Table 1 lists the N fertilizer guidelines for situations where the soil NO₃^--N test is not used. Apply the suggested rate of N fertilizer before planting. All sources of fertilizer should have an equal effect on yield.

Nitrogen fertilizer recommendations

Nitrogen, when needed, can come from several sources. If applied in a way to prevent loss, all sources of nitrogen have an equal effect on yield. When using either dry or liquid sources, the fertilizer N can be broadcast and incorporated before planting. If anhydrous ammonia is the preferred source, knife in the fertilizer before planting.

Table 1: Nitrogen fertilizer guidelines

Crop grown last year	Organic matter level*	Expected yield: 40-60 bushels per acre	Expected yield: 61-80 bushels per acre	Expected yield: 81-100 bushels per acre	Expected yield: 101-120 bushels per acre	Expected yield: 120 + bushels per acre
Alfalfa (4+ plants per square foot)	Low	0 lbs. N/acre	0 lbs. N/acre	0 lbs. N/acre	0 lbs. N/acre	0 lbs. N/acre
Alfalfa (4+ plants per square foot)	Medium and high	0 lbs. N/acre	0 lbs. N/acre	0 lbs. N/acre	0 lbs. N/acre	0 lbs. N/acre
Alfalfa (2 to 3 plants per square foot)	Low	0 lbs. N/acre	0 lbs. N/acre	20 lbs. N/acre	40 lbs. N/acre	60 lbs. N/acre
Alfalfa (2 to 3 plants per square foot)	Medium and high	0 lbs. N/acre	0 lbs. N/acre	10 lbs. N/acre	30 lbs. N/acre	50 lbs. N/acre
Soybeans Alfalfa (1 or fewer plants per square foot)	Low	0 lbs. N/acre	20 lbs. N/acre	40 lbs. N/acre	60 lbs. N/acre	80 lbs. N/acre
Soybeans Alfalfa (1 or fewer plants per square foot)	Medium and high	0 lbs. N/acre	0 lbs. N/acre	30 lbs. N/acre	50 lbs. N/acre	70 lbs. N/acre
Edible beans, field peas	Low	20 lbs. N/acre	40 lbs. N/acre	60 lbs. N/acre	80 lbs. N/acre	100 lbs. N/acre
Edible beans, field peas	Medium and high	10 lbs. N/acre	30 lbs. N/acre	50 lbs. N/acre	70 lbs. N/acre	90 lbs. N/acre
Group 1 crops	Low	0 lbs. N/acre	0 lbs. N/acre	0 lbs. N/acre	25 lbs. N/acre	45 lbs. N/acre
Group 1 crops	Medium and high	0 lbs. N/acre	0 lbs. N/acre	0 lbs. N/acre	15 lbs. N/acre	35 lbs. N/acre
Group 2 crops	Low	40 lbs. N/acre	60 lbs. N/acre	80 lbs. N/acre	100 lbs. N/acre	120 lbs. N/acre
Group 2 crops	Medium and high	30 lbs. N/acre	50 lbs. N/acre	70 lbs. N/acre	90 lbs. N/acre	110 lbs. N/acre

* low = less than 3.0%; medium and high = 3.0% or more.

Use these recommendations for oat production when the soil NO₃^--N test isn’t used.

Crops in Group 1:

Alsike clover, birdsfoot trefoil, grass/legume hay, grass legume pasture, fallow and red clover.

Crops in Group 2:

Barley, buckwheat, canola, corn, grass hay, grass pasture, oat, potato, rye, sorghum-sudan, sugarbeet, sunflower, sweet corn, triticale and wheat.

Phosphate, potash and other nutrients

The rates listed are appropriate for both broadcast and banded (drill applied) application. There is no research evidence with this crop to suggest that the banded placement is more efficient than a broadcast application.

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Phosphate recommendations

Use one of the following equations if you want a phosphate guideline for a specific soil test and a specific expected yield:

P₂O₅ rec = [0.644 - (0.032) (Bray P in ppm)] (Expected yield)

P₂O₅ rec = [0.644 - (0.041) (Olsen P in ppm)] (Expected yield)

Table 2: Phosphate fertilizer guidelines

Expected yield	0-5 parts per million (ppm) Bray and 0-3 ppm Olsen	6-10 ppm Bray and 4-7 ppm Olsen	11-15 ppm Bray and 8-11 ppm Olsen	16-20 ppm Bray and 12-15 ppm Olsen	21+ ppm Bray and 16+ ppm Olsen
40-60 lbs. per acre	30 lbs. of P2O5 per acre	20 lbs. of P2O5 per acre	10 lbs. of P2O5 per acre	0 lbs. of P2O5 per acre	0 lbs. of P2O5 per acre
61-80 lbs. per acre	40 lbs. of P2O5 per acre	30 lbs. of P2O5 per acre	15 lbs. of P2O5 per acre	0 lbs. of P2O5 per acre	0 lbs. of P2O5 per acre
81-100 lbs. per acre	50 lbs. of P2O5 per acre	35 lbs. of P2O5 per acre	20 lbs. of P2O5 per acre	0 lbs. of P2O5 per acre	0 lbs. of P2O5 per acre
101-120 lbs. per acre	60 lbs. of P2O5 per acre	45 lbs. of P2O5 per acre	25 lbs. of P2O5 per acre	10 lbs. of P2O5 per acre	0 lbs. of P2O5 per acre
121+ lbs. per acre	70 lbs. of P2O5 per acre	50 lbs. of P2O5 per acre	30 lbs. of P2O5 per acre	10 lbs. of P2O5 per acre	0 lbs. of P2O5 per acre

Potash recommendations

Use the following equations if you want a potash guideline for a specific soil test and a specific expected yield:

K₂O rec = [1.2773 - (0.0086) (Soil test K in ppm)] (Expected yield)

Expected yield	K soil test: 0-40 parts per million (ppm)	K soil test: 41-80 ppm	K soil test: 81-120 ppm	K soil test: 121-160 ppm	K soil test: 161+ ppm
40-60 lbs. per acre	55 lbs. N/acre	40 lbs. N/acre	20 lbs. N/acre	0 lbs. N/acre	0 lbs. N/acre
61-80 lbs. per acre	75 lbs. N/acre	55 lbs. N/acre	30 lbs. N/acre	0 lbs. N/acre	0 lbs. N/acre
81-100 lbs. per acre	95 lbs. N/acre	70 lbs. N/acre	40 lbs. N/acre	0 lbs. N/acre	0 lbs. N/acre
101-120 lbs. per acre	115 lbs. N/acre	85 lbs. N/acre	45 lbs. N/acre	10 lbs. N/acre	0 lbs. N/acre
121+ lbs. per acre	130 lbs. N/acre	90 lbs. N/acre	50 lbs. N/acre	10 lbs. N/acre	0 lbs. N/acre

Other nutrients

Except for the need for sulfur (S) when this crop is grown on sandy soils, other nutrients are not needed in a fertilizer program. For production on sandy soils, either use 10-12 lb. S/acre with the drill at planting or broadcast 25 lb. S/acre and incorporate before planting.

CAUTION! Do not apply more than 20 lb. N per acre as urea (46-0-0) with the drill. Do not place ammonium thiosulfate (12-0-0- 26) in direct contact with the seed. Do not place fertilizers containing boron in direct contact with the seed.

Daniel E. Kaiser, Extension nutrient management specialist